A rare case report of paediatric mucosal Schwann cell hamartoma presenting in the rectum with literature review

Mucosal Schwann cell hamartoma (MSCH) is a rare, benign lesion derived from Schwann cells, typically appearing as painless colonic polyps. Often an incidental finding, MSCH can be misdiagnosed, leading to unnecessary procedures. Unlike neurofibromas or schwannomas, MSCH is not linked to inherited conditions. We report the first case of rectal MSCH in a 6-year-old boy with painless rectal bleeding. A 0.7-cm distal rectal polyp was excised, and histology showed spindle cell proliferation in the lamina propria. Immunohistochemistry confirmed strong S100 positivity and negativity for epithelial membrane antigen and CD34, consistent with MSCH. This case is significant, given MSCH’s typical presentation in adult females, with only one previous paediatric case in the gall bladder. Due to its rarity, MSCH lacks definitive diagnostic criteria. Accurate diagnosis, based on histological and immunohistochemical features, is crucial to differentiate it from other polyps. Long-term follow-up is needed to understand its behaviour, as no recurrence or malignancy has been reported. This case underscores the importance of considering MSCH in paediatric patients with rectal polyps.